Fixing fiberglass bathtub crack

[Dick M.]

I bought a house with a crack in the sidewall of the tub. I can get to the back side of it and someone has tried to fix it before. I peeled off their fiberglass mat and it is sticky, like the resin never hardened. Should I try acetone to remove the leftover or just try to patch from inside the tub with an automotive product? Nice one piece tub shower outside of this...